will changing a 1 3/8 sway bar to a 1 3/4

[ukester]

make a huge difference in the handling of my jayco 31 ft precept?

[mel s]

Originally Posted by ukester

make a huge difference in the handling of my jayco 31 ft precept?

Probably not.

[twinboat]

I don't recall the exact increase in diameter but my 30 ft. Class C, Gulfstreams ride improved significantly with the upgraded rear sway bar.

Maybe not HUGE but very noticble.

[Yellowboat]

When my Roadmaster rear sway bar was installed the factory rear sway bar was not removed. It did make a difference in roll, or tilting from side to side.

A trac bar solves a different problem, tail wag.

If you are having handling problems there are things you can try before spending a lot of money.

You can search the cheap handling fix (CHF). CHF can help reduce sway.

You can weigh the four corners of your coach and compare to the carrying capacity of your axles. Remove or redistribute cargo if over weight or out of balance.

Go to your tire manufactures web site and find their inflation tables. You can use the tables to determine a safe PSI for the weight your axle is actually carrying. Use the heaviest side of an axle to determine tire pressure for all tires on that axle. Over inflation can cause a coach to wander and track.

So far you haven't spent very much money. Test drive after each change to see if you are happy with the changes.

If you have not had your coach aligned you might think about doing an alignment next. Ford aligns the chassis when they build it but the coach builder adds thousands of pounds to the chassis and does not check alignment.

If you want to save money there are instructions on how to build your own trac bar. Or you could get one installed.

You can have a sway bar installed if you still want better performance.

You can also think about a steering damper. I have a Safe-T-Plus but there are others.

Safe travels. JD

[JFNM]

Originally Posted by ukester

make a huge difference in the handling of my jayco 31 ft precept?

I doubt "huge". That said, you might try the less expensive option of replacing the sway bar bushings first. Depending on age or your rig, your's may be shot. New rubber is an improvement, urethane is a big improvement (but prone to squeaking if not lubed).

P.S. It is helpful to add a signature to your profile that includes vital information on your rig. Then folks don't have to guess or ask questions in response to your questions.

[TeJay]

A few weeks ago this same discussion came up and I got a lesson from a much more technical individual here on the forums. The F-53 SB's front VS rear are slightly different in diameter. Maybe two tenths of an inch. I also said it wouldn't make much difference. I got a lesson in mathematics from an engineer.

A 5/8" difference in SB diameters will make a HUGE difference in sway control. I don't know if I can find the post. If I can I'll follow up with another post with a link to it.

I found the post and got back before my chance to edit timed out. Here's the post and the measurements.

I measured the Ford SB at 1.500 & 1.405
That's 1-16/32" front
1-13/32" rear
The increase in twisting resistance was 1.29 times more with the slight increase in diameter. That increase is just over a tenth of an inch or .105. That's only an increase of 3/32"

Your sway bars are 5/8" or 20/32" larger. That's a HUGE difference.

If you want to read Peter Flynn's math explanation go to the CHF thread, page 230 and post# 3207. It's short and easy to read.

TeJay

[ukester]

I should have put that this is the front sway bar.

[TeJay]

Your question was, "Will a bigger SB make a HUGE difference?" YES!! Front or rear the math and the results will still apply. In the past some have only done the CHF on front SB. All resulted in improved sway control with good results.

Some changed or added sway bars and ended up with 2 on the rear. Same results. Better sway control.

TeJay

[Dennis Dean]

Originally Posted by TeJay

Your question was, "Will a bigger SB make a HUGE difference?" YES!! Front or rear the math and the results will still apply. In the past some have only done the CHF on front SB. All resulted in improved sway control with good results.

Some changed or added sway bars and ended up with 2 on the rear. Same results. Better sway control.

TeJay

I just added both a roadmaster front sway bar and the rear sway bar. The front is slightly thicker than the factory sway as TeJay just pointed out. One thing to me that was important was the steel in the roadmaster is twice the strength of the factory sway bar tho. I think this adds to the drivability. My coach is noticeably different in how it handles and drives. With the addition of the 5star tuner both my handling and engine performance are quite a bit different to the stock set up. I have both the roadmaster sway on the rear and the original factory sway as well. this is what roadmaster requires as part of the installation of the rear sway bar. My GVWR is 22K I will be looking at adding the SUMO springs next year for the fore and aft movement.

[Glenn NK]

Originally Posted by Dennis Dean

. . . . . One thing to me that was important was the steel in the roadmaster is twice the strength of the factory sway bar tho. I think this adds to the drivability.

The stiffness of all steel (very low strength right through to very high strength) is essentially constant no matter the strength of the steel.

Stiffness affects how much the bar will deflect under a given load, strength has nothing to do with this.

Strength only comes into play when the steel is bent to the point where it yields or stretches/compresses and will not return to the same shape before the load was applied.

Higher strength steel will carry a higher ultimate load than low strength steel will carry, but there is no difference in the amount of bending or deformation until the stress in the steel exceeds the yield point.

High strength steel is used in springs because they often undergo large deflections or deformations (think of coil springs in a car suspension). At high deformation, low strength steel would yield and not return to it's original shape. Not a great quality for a suspension.

In answer to the OP's question, changing the SB diameter from 1.375" to 1.75" would increase the stiffness by a factor of 2.624.

I think that would be a major change, but it's not the strength of the new SB that made the difference, it's the diameter increase.

Glenn